Abstract

The moderate resolution imaging spectro-radiometer (MODIS, Terra and Aqua) and ozone monitoring instruments (OMI) were used to investigate the spatio-temporal variations of aerosols over Nigeria. The cloud aerosol lidar and Infared Pathfinder satelite observations (CALIPSO) were used for cloud aerosol classification in order to show aerosol concentration within the planetary boundary layer (PBL). 4 years data were selected so as to be able to observe seasonal variation on the aerosol loading and to identify the year(s) and month(s) that experienced highest aerosol plume. Aerosol optical depth (AOD) of 2.30 µg/m3 occurred in March, 2012 at the shoreline of South–South, Nigeria while 1.25 µg/m3 was recorded in June, 2011 in Plateau State, North-Central, Nigeria. Dominant aerosols found around the shore line of the country were rich in sulfate as it shows hygroscopic characteristics and exhibited seasonal variation for the 4 years experimented. It was observed that petroleum refinery operations and gas flaring significantly contributes to the major sources of sulfate aerosol which would likely increase aerosol optical depth over the region. Strong outbreak of dust experienced over Nigeria from 500 to 1500 m originated from the continental sources in the Saharan desert, Mediterranean sea and other biomass burning in the Niger Delta.

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Acknowledgements

We thank National Aeronautical and Space Administration (NASA) of United State of America for providing Giovanni software that was used in this work not only that the site also provide links to remote sensing dataset at different spatial and temporal resolution. We also appreciate the provision of the CALIPSO aerosol products at http://www.icare.univ-lille1.fr/archive. We are very grateful to individual for their informative comments which have greatly improved the quality of this work.